Proposed research in the area of carbon-13 nuclear magnetic resonance (NMR) is directed towards developing spectroscopic techniques and theory. Signal enhancement techniques using magnetization transferring pulse sequences is proposed. The development of a high velocity solids spinner coupled with a proton decoupler will provide a high resolution solids NMR capability to the program. Coupled spin-relaxation has been shown in small molecules to be valuable method for characterizing molecular motion and structure. It is proposed that these techniques now be used to study segmental and overall motion in larger molecules such as lipids, steroids, proteins, etc. Carbon-13 NMR applications in such varied areas as 5S-ribosomal RNA, bile micelles, and perfused organs such as hearts, kidneys, etc. Work on the theoretical basis of chemical shifts and of statistical mechanical treatments of molecular motion will be ongoing.